I'd say cultural and environmental. By the time we get to the GAotS era, the Sith worlds are so replete with dark side energy that even if you somehow managed to eradicate the culture, anyone raised on those worlds would likely wind up corrupt.

EDIT:
As for where the dark side culture "came from" in the first place, I would imagine it went the same way as always. The Sith species discovered the Force, a bunch of different traditions arose around its use... and then one of those traditions -- in this case a dark side one -- beat out all the rest.

I'd say cultural and environmental. By the time we get to the GAotS era, the Sith worlds are so replete with dark side energy that even if you somehow managed to eradicate the culture, anyone raised on those worlds would likely wind up corrupt.

EDIT:
As for where the dark side culture "came from" in the first place, I would imagine it went the same way as always. The Sith species discovered the Force, a bunch of different traditions arose around its use... and then one of those traditions -- in this case a dark side one -- beat out all the rest.

For a planet to have Dark Side energy, there has to have been Dark Side use and/or dead darksiders on that planet.

As for where the dark side culture "came from" in the first place, I would imagine it went the same way as always. The Sith species discovered the Force, a bunch of different traditions arose around its use... and then one of those traditions -- in this case a dark side one -- beat out all the rest.

Read that. His only "passion" (which the Sith Code requires) is honor. He actually becomes a Jedi, and a loyal servant of the light side. So there you go: cultural, tradition...but not hard-wired into their blood.

Read that. His only "passion" (which the Sith Code requires) is honor. He actually becomes a Jedi, and a loyal servant of the light side. So there you go: cultural, tradition...but not hard-wired into their blood.

So? You're going to argue that he's still technically dark-sided because he has a single passion? I'd say practically every Jedi has some passion or another. He just doesn't use rage, hatred, lust, etc. like the other Sith. He's certainly not dark. Gray, maybe, but more likely light and definitely not dark.

So? You're going to argue that he's still technically dark-sided because he has a single passion? I'd say practically every Jedi has some passion or another. He just doesn't use rage, hatred, lust, etc. like the other Sith. He's certainly not dark. Gray, maybe, but more likely light and definitely not dark.

No. I was just asking about the possibility of a Red Sith without passion.

"Passion. Passion and anger and love. That's what this galaxy needs, not serenity. Passion for change. Anger at this brutality. Love - buckets of it, for everyone, love between child and parent, between spouses, between brothers and sisters, between friends. We need more attachment, not less. Attachment can stop us from tearing ourselves apart."

"King Adas was a massive, regal being encased in majestic ebon warrior armor. Raised from his youth as a chosen being due to the charcoal pigment of his skin, Adas demonstrated great intelligence, fighting prowess, and a tremendous aptitude for Sith magic. With his alchemically forged battle-ax, Adas led the bloody unification of Korriban's disparate nations and became its undisputed world ruler. The Sith people came to believe that King Adas was immortal and that his reign would be eternal."

Given the above, I have no idea why TOR's codex would suggest that Adas was an untrained Force sensitive. Bizarre.

And I'd forgotten all about this nugget:

"Some historians have speculated that the attitudes of the early Sith people were owed to a prehistoric encounter between their species and the vampiric beings known as the Anzati."

"Passion. Passion and anger and love. That's what this galaxy needs, not serenity. Passion for change. Anger at this brutality. Love - buckets of it, for everyone, love between child and parent, between spouses, between brothers and sisters, between friends. We need more attachment, not less. Attachment can stop us from tearing ourselves apart."

True, but this thread isn't about whether the PT Jedi are right or wrong.

"King Adas was a massive, regal being encased in majestic ebon warrior armor. Raised from his youth as a chosen being due to the charcoal pigment of his skin, Adas demonstrated great intelligence, fighting prowess, and a tremendous aptitude for Sith magic. With hisalchemically forged battle-ax, Adas led the bloody unification of Korriban's disparate nations and became its undisputed world ruler. The Sith people came to believe that King Adas was immortal and that his reign would be eternal."

Given the above, I have no idea why TOR's codex would suggest that Adas was an untrained Force sensitive. Bizarre.

And I'd forgotten all about this nugget:

"Some historians have speculated that the attitudes of the early Sith people were owed to a prehistoric encounter between their species and the vampiric beings known as the Anzati."

"untrained" could mean that Adas didn't know everything that a Jedi would.

Very likely both. It probably started out as cultural, but if there are some combination of traits that predisposes someone to have a personality amenable to falling to the dark side then I'm sure that the people with those traits won out. Of course, we only have like what, a thousand generations to work with, but that's enough for a little bit I think.